Scale Run

The map is drawn on a logarithmic zoom: every time the view grows ten times wider, you have moved one power of ten. Sizes and distances from the chosen center are true to scale. Directions are not: real objects lie all over the sky, so the game spreads them around the map to keep them readable. The shapes of galaxies and clusters, and the outline of Laniakea drawn as a circle around the Great Attractor, are approximate.

Your score is how many powers of ten you are off, the error astronomers use for rough estimates. Guessing 200,000 km for the Moon (384,400 km) is off by a factor of 1.9, or 0.28 powers of ten. Three stars need an average miss within 0.2 powers of ten, a factor of 1.6.

Light-travel time ties every scale together: light covers the Moon's distance in 1.3 seconds, 1 AU in 8.3 minutes and the distance to Proxima Centauri in 4.2 years. The last level adds expansion: the oldest light, the cosmic microwave background, has traveled for about 13.8 billion years, but the matter that sent it is now about 46 billion light-years away, because space stretched while the light was in flight. We computed that radius for the Planck 2018 cosmological parameters; you will also see 46.5 billion, from older parameter sets.

Sources: NASA planetary fact sheets, the IAU 2012 definition of the astronomical unit, NASA on Voyager 1, ESA Gaia DR3, Joyce et al. 2020 (Betelgeuse), GRAVITY Collaboration 2021 (Galactic Center), NASA on the Milky Way, Pietrzynski et al. 2019 (Large Magellanic Cloud), NASA on Andromeda, Mei et al. 2007 (Virgo Cluster) and Tully et al. 2014 (Laniakea).